#include <bits/stdc++.h>
#include <cstring>
using namespace std;
queue<string> a;
queue<int>q;
int space;
string goal;
int fx[6] {-3,-1,1,3};
map <string,int> p;
int bfs(string x) {
	a.push(x);
	int cnt=0;
	q.push(0);
	while(!a.empty()) {
		cnt++;
		string b=a.front();
		int t=q.front();
		if(b==goal) {
			return t;
		}
		space=b.find('0');
		q.pop();
		a.pop();
		for(int i=0; i<4; i++) {
			int nx=space+fx[i];
			if(nx<0 or nx>8 or (space==3 and fx[i]==-1) or (space==2 and fx[i]==1) or (space ==5 and fx[i]==1) or (space == 6 and fx[i]==-1) or (space==2 and fx[i]==-3) or (space==8 and (fx[i]==1 or fx[i]==3)) or (space == 6 and (fx[i]==-1 or fx[i]==3))) continue;
			if(space==7&&fx[i]==3)continue;
			if(space==1&&fx[i]==-3)continue;
			if(space==1&&(fx[i]==-3||fx[i]==-1))continue;
			swap(b[space],b[nx])
			if(!p.count(b)) {
				p.insert({b,cnt});
				a.push(b);
				q.push(t+1);
			}
			swap(b[space],b[nx]);
		}
	}
	return -1;
}
int main() {
	string s;
	cin>>s;
	p[s]=0;
	goal="123804765";
	if(s==goal) cout<<0;
	else {
		cout<<bfs(s);
	}
}

58pts求调